content是UILabel（contentLabel）的字符串内容，contentLabel是UILabel
NSMutableAttributedString *attStr = [[NSMutableAttributedString alloc]initWithString:content];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc]init];
[style setLineSpacing:5.0f];
CGFloat textWidth = self.contentLabel.bounds.size.width;
NSInteger leng = textWidth;
if (attStr.length < textWidth) {
leng = attStr.length;
}
[attStr addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, leng)];
//Label获取attStr式样
self.contentLabel.attributedText = attStr;
[self.contentLabel sizeToFit];
